Abstract:

Harmful algal blooms (HABs) release toxic compounds in water and are increasing in frequency worldwide due to eutrophication. One HAB toxin, the neurotoxin β-methylamino-L-alanine (BMAA), has garnered much attention over the past twenty years, but questions remain regarding its presence and distribution within the bodies of fish exposed to HABs. We evaluated the presence and tissue distribution of BMAA and its isomers, N-(2-aminoethyl) glycine (AEG), 2,4-diaminobutyric acid (DAB), and β-amino-N-methylalanine (BAMA), in yellow perch and walleye sampled in Lake Erie near Point Pelee, Ontario, a region known for its seasonal HABs. BMAA isomers were quantified in eight fish tissues (brain, muscle, liver, heart, kidney, gills, gonads, and scales) using liquid chromatography with tandem mass spectrometry. Overall, BMAA was the isomer detected the least frequently and at the lowest concentrations, while AEG was detected in nearly all samples at consistently high concentrations. Patterns of isomer concentrations varied between tissues, with species differences in the brain (BMAA higher in perch and DAB higher in walleye) and kidneys (DAB higher in walleye). The findings highlight that isomers of BMAA may represent a greater risk to aquatic wildlife than BMAA itself, but more research on exposure route, bioaccumulation, and metabolism of these neurotoxins will be required to better understand the risk they pose to fish. Funded by the Great Lakes Fishery Commission and by NSERC through the Canada First Research Excellence Fund and Discovery Grant programs.